Muscle Activity, Mechanical Work and Efficiency at Ventilatory Threshold During Maximal and Sub-Maximal Treadmill Exercise
Bibliographic record
Abstract
0192 PURPOSE: To examine the effects of maximal and sub maximal steady-state treadmill exercise on muscle recruitment and activation, their relationships with the mechanical work and efficiency. METHODS: A group of thirteen non-endurance trained male subjects were exposed to an incremental maximal treadmill test during which oxygen consumption and electromyography (EMG) were collected. Fortyeight hours following the maximal test, two 10-minute constant workload treadmill exercise at intensities of 20% above (supra-VT) and below (sub-VT) the ventilatory threshold (VT) determined during the VO2max test. During these two tests the oxygen consumption and the EMG were monitored. A digital video camera was used to capture individual motions during the max and the sub-max on treadmill. The subjects were also asked to run on a 10 meters platform passing through a force plate at the supra-VT and sub-VT speeds. The 4 sub maximal tests were randomly assigned and separated by at least 15 minutes of passive rest. RESULTS: The iEMGexercise intensity relationships showed a strong and significant correlation for each muscle monitored suggesting a linear relationship; r = 0.75, 0.86, 0.83 for the vastus lateralis (VL), biceps femoris (BF), and gastrocnemius lateralis (GL) respectively. Based on the subsequent findings of paired t-tests this relationship was found to have a threshold during the incremental test. Further this iEMG threshold was correlated (r = 0.81) to the ventilatory threshold (VT) as determined from metabolic parameters. A significant iEMG threshold was also noted in the VL during the supra-VT workload. The muscle activity during the incremental test was significantly greater than the muscle activity from the same muscle during the sub maximal workloads when matched for VO2, workload and respiratory exchange ratio (RER). The mechanical efficiency decreased as the intensity increased during the max test and the two sub max tests. CONCLUSIONS: The inability of the current study to determine the specific mechanism of the EMG thresholds despite the correlation with the VT, suggests that no conclusion can be made regarding the relationship that may exist between these 2 parameters. Although not clearly depicted in the current results, the activation of agonist muscles within each functional group of muscles of the lower limb is the likely mechanism of the discrepancies in muscle activation between the incremental and the constant workload exercises.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".